共查询到20条相似文献,搜索用时 62 毫秒
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用门尼粘度仪、凝胶渗透色谱仪、乌氏粘度计、华莱士快速塑性计和RPA2000橡胶加工分析仪测试天然橡胶(NR)的相对分子质量,研究其与加工性能的相关性。结果表明:门尼粘度仪测试的全乳型(SCRWF)和标准(SCR20)NR的门尼粘度和应力松弛系数(α)差异性小,很难区分相对分子质量;其他方法测试的参数相关性好,均可以表征NR的相对分子质量;与SCRWF相比,SCR20的平均相对分子质量、粘均相对分子质量、可塑度和RPA2000橡胶加工分析仪测试的α均较小,加工性能较好;用RPA2000橡胶加工分析仪在120℃、0. 1 Hz下进行应变扫描,SCRWF和SCR20的储能模量(G′)比值以及SCR20和SCRWF的损耗因子(tanδ)比值最大,应变对G′和tanδ的影响不大。 相似文献
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研究国内外不同软化点的抗湿滑树脂在轮胎胎面胶中的应用。结果表明:在胎面胶配方中,采用10份不同抗湿滑树脂等量替代环烷油,胶料的门尼粘度均有所提高,FL和Fmax均小幅上升,门尼焦烧时间和t90变化不大;硫化胶的硬度、定伸应力和拉伸强度略有提高,撕裂强度和耐磨性能变化不大;胶料的玻璃化温度升高,0 ℃时的损耗因子(tanδ)大幅增大,可显著改善抗湿滑性能;60 ℃时的tanδ变化不大,对滚动阻力影响较小。由线性回归分析可知,胶料的压缩疲劳温升与橡胶-树脂相容性存在一定相关性,针对不同橡胶基体选择相容性最佳的树脂是降低胶料滞后生热的关键。 相似文献
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介绍了滚动阻力及将低滚动阻力的意义,总结了滚动阻力的不同测试方法。对于实验室内针对橡胶半成品试样测定滚动阻力的试验方法,旋转功率损耗仪以及动态粘弹谱仪,从滚动过程导致的能量损失方面分析了其不同之处。前者是一种定负荷状态下测定的周期过程中的能量损失,该能量损失与胶料的损耗因子和弹性模量的比值成正比;而后者是在固定应变状态下测定的胶料损耗因子,是一个相对的表征,而不是直接测定的滚动阻力,该种测试下,胶料的滞后损失与胶料的损耗因子和弹性模量的乘积成正比。这二者并不相同,但是旋转功率损耗仪测定的能量损失与粘弹谱仪测定的损耗因子与弹性模量的乘积之间有较好的线性相关性。 相似文献
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使用RPA2000橡胶加工分析仪,研究偶联剂Si69用量、白炭黑用量、增塑剂种类、硫化体系和粘合剂RH对丁苯橡胶(SBR)胶料损耗因子(tanδ)的影响。结果表明,加入偶联剂Si69能够减小胶料的tanδ,且偶联剂Si69的最佳用量为白炭黑用量的10%。当白炭黑用量不大于40份、应变小于1%时,随着白炭黑用量的增大,胶料的tanδ减小;白炭黑用量不大于40份、应变大于1%时,随着白炭黑用量的增大,胶料的tanδ增大;当白炭黑用量大于40份时,胶料的tanδ急剧增大。加入不同种类的增塑剂均可使胶料的tanδ增大,其中加入石蜡油的胶料的tanδ比加入白油膏和古马隆树脂的胶料小。随着硫黄用量的增大,硫黄硫化体系胶料的tanδ先减小后增大,硫黄用量为2份时胶料的tanδ最小;硫黄与过氧化物并用硫化体系的胶料的tanδ比单用硫黄胶料小,且随着硫化剂双25用量的增大,胶料的tanδ减小。加入粘合剂RH可减小胶料的tanδ。 相似文献
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针对于缝洞型碳酸盐岩储层,酸化压裂改造工艺已经成为重要的增储上产措施。而压裂液的滤失,极大的影响了酸化压裂的整体效果。进一步优化和完善酸化压裂注入液体系,对提高酸化压裂效果显得更为重要。通过调整稠化剂及交联剂分子结构以及优化体系配方,解决了交联酸酸液体系稳定性问题,实现深度酸压提供技术保障。分析了硅粉、淀粉和分散液三种暂堵降滤失剂的优缺点,提出了暂堵降滤失剂物理、和化学要求,采用可降解合成高分子颗粒材料将达到良好暂堵滤失效果。并结合研究区碳酸盐岩储层温度特点及压裂工艺的需求,通过现场试验,完成了120~160℃高温压裂液配方体系。 相似文献
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Chaim Aharoni Jonathan Inbar 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1973,23(5):333-338
During the oxychlorination process, there are losses of copper from the catalyst as a result of a reaction with the walls of the reactor: the cupric ions are reduced to metallic copper and deposited on the walls. We have observed rates of deposition of the order of 10?2 g of copper per cm2 of walls per year, for walls of pure iron. The deposited copper was detected and estimated by electron-probe microscopy. Attrition does not appreciably change the concentration of copper in the catalyst particles. 相似文献
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Microwave Dielectric Loss of Titanium Oxide 总被引:8,自引:2,他引:6
Alan Templeton Xiaoru Wang Stuart J. Penn Stephen J. Webb Lesley F. Cohen Neil McN. Alford 《Journal of the American Ceramic Society》2000,83(1):95-100
The dielectric loss (tan δ) of titanium dioxide (TiO2 ) disks has been measured at a frequency of 3 GHz. High-purity TiO2 sintered to almost-full density exhibits a very high tan δ, which is interpreted to be due to oxygen deficiency. To counter this, doping with stable divalent and trivalent cations, such as Mg and Al, leads to a low tan δ, probably by preventing Ti4+ reduction. The tan δ of polycrystalline TiO2 doped with divalent and trivalent ions with ionic radii in the range of 0.5–0.95 Å at 3 GHz can be very low: 6 × 10−5 ( Q ∼ 17 000) at a temperature of 300 K. The tan δ of undoped pure TiO2 disks increases when the disks are cooled from 300 K to ∼100 K. At temperatures <100 K, the tan δ decreases rapidly, which is interpreted as carrier freeze-out. The tan δ for all the high- Q doped TiO2 polycrystalline samples smoothly decrease to ∼5 × 10−6 ( Q ∼ 200 000) at 15 K, comparable to that of single crystals. 相似文献
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浮子流量计压力损失的实验研究 总被引:1,自引:0,他引:1
在相同流动条件下,对不同口径、不同流量范围的锥管浮子流量计和孔板浮子流量计的压力损失进行了实验研究。实验研究发现,浮子流量计的压力损失并非定值,而是随流量的增大而增大;和锥管浮子流量计相比,相同口径的孔板浮子流量计的压力损失更大。考虑流体粘性后,分析了浮子流量计实际压力损失的构成,并以100 mm口径的锥管浮子流量计和孔板浮子流量计为例,对其压力损失进行了估算。 相似文献
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S. H. Park H. O. Kim Y. T. Han S. B. Kwon K. W. Lee 《Aerosol science and technology》2013,47(3):710-717
Wall loss rates of polydispersed aerosols in a stirred vessel were studied theoretically and experimentally. A formula for the poly- dispersity factor of the wall loss rate was derived using the moment method of log-normal size distribution and compared with numerical calculations. The representative theory of Crump and Seinfeld (1981) was used as the wall loss rate of monodispersed aerosols in which the Brownian diffusion, the turbulent eddy diffusion, and the gravitational settling are included as wall loss mechanisms. The results of the analysis show that the wall loss rate of a polydispersed aerosol is substantially higher than that based on a monodispersed size distribution model if the particle size distribution can be represented reasonably well by a log-normal function. The existing diagram showing the loss rate as a function only of the particle size was expanded to include the polydispersity effects. Experimental measurements of particle wall loss rate were performed by observing the time-dependent changes in particle number concentration for various stirring intensities in a cylindrical stirred chamber. It was shown that by correcting for the polydispersity effect, the dependence of the wall loss rate on particle size and stirring intensity agreed with the theory of Crump and Seinfeld (1981). 相似文献
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The object of this research was to develop ultra low loss ceramic dielectrics. The possible causes of the dielectric loss of ceramic bodies were first analyzed theoretically. Experimental bodies, designed on the basis of this analysis, provide for ultra low dielectric loss. 相似文献